1. Field
Apparatuses and methods consistent with example embodiments relate to a semiconductor memory, and more particularly, relates to a nonvolatile memory device and an operation method thereof.
2. Description of Related Art
A semiconductor memory refers to a memory device that is implemented using semiconductor such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), indium phosphide (InP), or the like. A semiconductor memory device is roughly divided into a volatile memory device and a nonvolatile memory device.
A volatile memory device refers to a memory device that loses data stored therein at power-off. The volatile memory device includes a static random access memory (SRAM), a dynamic ram (DRAM), a synchronous DRAM or the like. A nonvolatile memory device refers to a memory device that retains data stored therein even at power-off. The nonvolatile memory device includes a read only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable and programmable ROM (EEPROM), a flash memory device, a phase-change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), a ferroelectric RAM (FRAM), or the like.
Because a response speed and an operation speed of the DRAM are fast, the DRAM is widely used as a main memory of a system. However, because the DRAM is a volatile memory in which data is lost when a power is shut off, a separate device is used to retain data stored in the DRAM. In addition, because the DRAM stores data using capacitors, the size of a unit cell is large, thereby making it difficult to increase a DRAM capacity within a restricted area.